1. Field of the Invention
This invention relates generally to a system for identifying a hard target from a distance, and particularly relates to small elements deliverable from an airborne vehicle and capable of acquiring a large kinetic energy.
2. Description of the Prior Art
In the past it has been attempted to destroy hard targets from a distance by conventional warheads. Such hard targets may, for example, consist of a concrete road, a metal bridge, or moving vehicles, such as tanks and armored cars. Because of the errors associated with the location of the target and the warhead delivery system, many warheads must be delivered to produce a single direct hit on such a hard target. Additionally, many direct hits are required to destroy a hard target because of its strong construction.
In order to reduce the number of warheads required to destroy a target, modern weapons utilize expensive seekers and guidance system. Such system must distinguish the target from its background and maintain lock-on until the warhead detonates.
It has also been proposed to designate from a distance the target, for example, by means of a laser beam. Nevertheless, the designation system must be disposed relatively close to the target to provide satisfactory illumination of the seeker of the homing vehicle for its proper operation. Hence, the personnel operating the laser become rather vulnerable.
Many systems have been evolved in the past to designate hard targets. Among these is patent 3,358,602 which issued to Chope. The patent discloses a nuclear radiation generating system to reveal the location of enemy troops or equipment. To this end, beta-emitting particles are mixed with the gunpowder to be used for ammunition which somehow falls into the hands of the enemy. When the ammunition is fired, the gun barrel becomes an emitter of X-rays which can now be detected by airborne sensors.
The patent to Mathes et al., No. 3,526,198 is directed to an anti-submarine attack method. Sonar is utilized at long ranges to locate submerged submarines. A high-speed and a low-speed vehicle are utilized as well as standard sonar techniques. The sonar signal is generated from the friendly vehicle and the system depends on an echo from the submarine hull for location of the submarine.
The U.S. patent to Handler et al., No. 3,712,228, discloses a target marker warhead. The conventional warhead on a guided missile is replaced by a large spotting charge. The spotting charge detonates by means of a standard fuse which provides an aim point for subsequent missiles. Hence, the problem still remains that the target must first be detected and discriminated by some other means.
Various armor piercing bombs and similar devices have been devised in the past. Among these is the U.S. patent to Nichols, No. 2,422,920 which discloses an armor piercing drop bomb. Reaction forces are utilized to accelerate the armor piercing bomb to velocities sufficient to penetrate armor. The U.S. patent to Riparbelli, No. 3,935,817 discloses a penetrating spear. Here rocket propulsion is combined with the kinetic energy penetrator to destroy armor targets. In this case, a rocket motor is used to provide the spear with sufficient kinetic energy.
The U.S. patent to Peterson, No. 3,483,837, discloses a streamlined missile for the location of submarines which is launched from a ship into the water. The missile is provided with a magnet to attach itself to the submarine. The missile further contains a normally inactive pressure-responsive acoustic source activated by the water pressure when the missile adheres to the submarine. The acoustic source then signals the presence of the submarine.